HOUSTON — Wealth has never had a stigma in the affluent suburbs of Fort Worth, where the town of Westlake landed, to no one’s surprise, on Forbes’ list of America’s most affluent neighborhoods last year with a median income of $250,000.

But in recent days, the implications of being rich have set off an emotional, angry debate that has stretched far beyond the North Texas suburbs, after a juvenile court judge sentenced a 16-year-old from a well-off family to 10 years’ probation for killing four people in a drunken-driving crash.

The judge, Jean Boyd, on Tuesday declined to give the teenager, Ethan Couch, the punishment sought by Tarrant County prosecutors — 20 years in prison — and instead ordered him to be placed in a long-term treatment facility while on probation. Judge Boyd did not discuss her reasoning for her order, but it came after a psychologist called by the defense argued that Mr. Couch should not be sent to prison because he suffered from “affluenza” — a term that dates at least to the 1980s to describe the psychological problems that can afflict children of privilege.

Prosecutors said they had never heard of a case where the defense tried to blame a young man’s conduct on the parents’ wealth. And the use of the term and the judge’s sentence have outraged the families of those Mr. Couch killed and injured, as well as victim rights advocates who questioned whether a teenager from a low-income family would have received as lenient a penalty.

“We are disappointed by the punishment assessed, but have no power under the law to change or overturn it,” one of the prosecutors, Richard Alpert, said in a statement.

But despite the national attention the case has received — “Being rich is now a get-out-of-jail-free card,” read a headline at TheWeek.com — the role that the wealth of Mr. Couch’s family played in his sentence, and whether the judge had in any way been influenced by the psychologist’s testimony, remained unclear.

Criminal defense lawyers said it was not uncommon for minors involved in serious drunken-driving cases and other crimes to receive probation instead of prison time, even in a tough-on-crime region such as North Texas. Other experts said it was part of a growing trend of giving a young person a second chance through rehabilitation instead of trying him as an adult.

Liz Ryan, the president and chief executive of the Campaign for Youth Justice, a group in Washington that advocates for juvenile rehabilitation, said that in a series of recent cases before the Supreme Court and state courts, advances in neuroscience have been applied to questions of crime and punishment for young people.

“They make mistakes, they’re prone to impulsive behavior,” Ms. Ryan said. “And at the same time, they are capable of change.”

But a prominent advocate for victims’ rights reacted to the sentence with scorn. “Just when you think our excuse-making culture has sunk as low as it can go, somebody goes yet lower,” said Kent Scheidegger, the legal director of the Criminal Justice Legal Foundation in Sacramento.

Scott Brown, Mr. Couch’s lawyer, said that while the word affluenza may have become an object of fascination, it was never at the heart of the case. His client had already pleaded guilty, and the word came up in hearings on punishment. “I never used the word affluenza, and never would have used such a cute word in such a serious, tragic case,” Mr. Brown said. “That’s just been blown completely out of proportion.”

Mr. Couch’s parents, Fred and Tonya Couch, own homes in Fort Worth and the nearby suburb of Burleson, where the crash occurred. Fred Couch runs a sheet-metal company. On the night of June 15, Ethan Couch and several friends stole beer from a Walmart and went to his parents’ Burleson home to have a party. Later, he and seven others crowded into the pickup truck owned by his father’s company to go to a store.

Prosecutors said Mr. Couch swerved off Burleson-Retta Road, killing four pedestrians: Breanna Mitchell; Hollie Boyles and her daughter Shelby, 21; and Brian Jennings. Tests showed that Mr. Couch had a blood-alcohol level of 0.24, three times the legal limit for drivers.

Hollie and Shelby Boyles had left their house that night to assist Ms. Mitchell, a stranger whose car had broken down. “I’m sure the judge is doing what she thinks is probably right for Ethan’s rehabilitation,” said Eric Boyles, Shelby’s father and Hollie’s husband. “But from the victims’ standpoint, she underestimated the impact. Words can’t describe how disappointed I am in terms of how the judicial system works.”

Two teenagers riding in the bed of the pickup were thrown from the vehicle. One of them, Sergio Molina, 15, suffered a severe brain injury and remains in a minimally responsive state. His family filed a suit against Mr. Couch, his parents and his father’s company.

Bill Berenson, a lawyer for Mr. Molina’s parents, said his clients were stunned by the sentence. “Their son is paralyzed, four people are dead and the perpetrator gets his wrists slapped,” he said. “How could they not feel that his affluence kept him from serving time?”

Manny Fernandez reported from Houston, and John Schwartz from New York.

A version of this article appears in print on , on Page A11 of the New York edition with the headline: Teenager’s Sentence in Fatal Drunken-Driving Case Stirs ‘Affluenza’ Debate. Order Reprints | Today’s Paper | Subscribe